{
Question:
What is the most easy way to set a same font name to all controls
in project in run time?

Answer:
By default all controls have ParentFont = true, so if you did not change
that for specific controls you could just change the forms Font
property, e.g. in code attached to the Screen.OnActiveFormChange event.
If you cannot rely on all controls having Parentfont = true you would
have to loop over all controls on the form and set the font property for
each or at least for those that have ParentFont set to false. You can
use the routines from unit TypInfo for that, they allow you to access
published properties by name. The code, again sitting in a handler for
Screen.onActiveFormChange, would be something like this: